1. Field of the Invention
The invention is in the field of protective helmets for sports, the military, and the like.
2. Background Art
Sports helmets are well known. Early sports helmets were made of leather. Modern sports helmets typically have an exterior shell made of a rigid injection molded resin with an inner layer of padding to protect the player's head. Some of these conventional sports helmets include an inflatable bladder. See for example U.S. Pat. No. 8,881,315. For other helmet constructions, see U.S. Pat. Nos. 8,938,818, 8,947,195, 8,713,716 and U.S. Pat. No. 8,719,967. The disclosures of the foregoing U.S. patents are incorporated by reference herein.
Virtually all sports and military helmets include a rigid impact resistant shell made of various materials. For example, modern football helmets often have a tough rigid impact resistant outer shell made of polycarbonate alloy plastic. Another material used widely in protective headgear is ABS polymer (Acrylonitrile Butadiene Styrene). Bicycle helmets have an outer shell made of an impact absorbing molded expanded polystyrene foam. Modern military helmets have a rigid impact resistant outer shell containing Kevlar. All of the materials making up the rigid outer shell of such helmets are lightweight, durable, strong, and rigid. The materials have good shock absorbance and impact resistance.